【Intensify】 , 【aggravate】 , 【heighten】 , 【enhance】 mean to increase markedly in degree or measure.
【Intensify】 implies a deepening or strengthening of a thing or especially of its characteristic quality.
【Aggravate】 implies a manifest increase in the seriousness of a situation or condition that is already unpleasant or difficult.
【Heighten】 and 【enhance】 both imply a lifting or raising; 【heighten】 , however, tends to imply a lifting above the ordinary, the trite, or the commonplace, and a consequent increase in sharpness and poignancy, and 【enhance】 a lifting above the norm or the average in desirability or attractiveness by the addition of something that increases the value, charm, or prestige of the thing enhanced.